Gas engine safety cap



July 1, 1947. EMERY 2,423,181

GAS ENGINE SAFETY CAP Filed Dec. 15, 1945 F VI/111111.714

A. III:

INVENTOR. MR. EMERY BY %Z Z ATTORNEYS Paiented July 1, 194'? GAS ENGINE SAFETY CAP Melvin R. Emery, Kansas City, Kana, assignor to Phillips Petroleum Company, a corporation of Delaware Application December 13, 1945, Serial No. 634,842

2 Claims. (01. 123-488) This invention relates to gas engines. In one caused by leakage of combustible gas around of its more specific aspects it relates to a safety valve stems of gas injection valves. cap device for use inconjunction with a gas en- Other objects and advantages will be appargine fuel injector. cut to those skilled in the art from a study of In the pe t n f gas ngines, natural or 5 the following disclosure when taken in conjuncother combustible gas is used as fuel. Such ention with the accompanying drawing, which forms gines may operate to draw fuel into the cylinders a part of this specification. by suction of the intake stroke. When gas en- The figure is a diagrammatic cross sectional gines are in heavy duty service, not enough gas view of one embodiment of my safety cap device. can be drawn into a cylinder to do the required Referring now to the drawing, reference nuwork on account of the relatively low thermal meral I refers to a valve stem having a poppet value of normally gaseous fuel. In such cases type valve head 2, a valve guide 3, a further valve the fuel is ordinarily injected or pumped under guide 4 and a stuifing box assembly 5. The pressure into the cylinders.- The source of oxystufiing box 5 is composed of the usual member gen for combustion is usually atmospheric. some parts, a threaded base member 6, a gland nut gas engines are 2-cycle engines, and sufficient 1, a gland member 8 and some packing 9. air remains after the scavaging operation to sup- The valve guides 3 and 4, etc. are integral with port combustion for the power stroke to follow. a valve body H], which, in ordinary construction, In this case, following the scavaging operation, is usually a casting. Bolt holes Ila and lib when the piston rises on the compression stroke, are provided for rigidly attaching the valve asan inlet fuel valve opens and the fuel is injected. sembly to an engine head which, of course, has Such injection is complete as the piston apthread bolt holes to receive bolts. A channel proaches the top of its stroke and prior to igl3 terminates at the exterior of the valve body nition. at a threaded opening l2, which opening is for When gaseous fuel is injected into the cylinders attachment to a source of fuel gas, not shown. under pressures of the order of 15 to 20 pounds The channel l3 extends from point [2 around per square inch gauge, the fuel valves frequentbolt hole Ila, passes valve guide 3 and termily leak gas in spite of design and construction nates in a valve seat l4 upon which the valve precautions. One such valve will hereinafter be head 2 rests when the valve is in a closed pofully described. sition.

Leakage around these Valve stems, obviously, A rocker arm pivot member I5 is shown as cast provides material for a fire or an explosion. In integral with the valve body [0. The rocker arm, one type of gas engine widely used, the design is which pivots at pivot member l5 and extends to such that the pressured fuel inlet valve is sitcontact the valve stem at the end [6, is not shown uated rather close to a spark plug. Any sparkfor purposes of simplicity. ing or short circuiting at the outer end of the A compression spring H, in conjunction with spark plug may promote an explosion. a spring retainer Washer member l8, operates I have found that in the normal operation of to hold the valve head 2 in a closed position exsuch gas engines that small explosions and fires cepting when. the rocker arm (not shown), by in the vicinity of the fuel injection valve are 40 pre s re t point l6 pens th v lve nst sa d common. Asfar as the engines are concerned, compression spring. these small fires or explosions do not ordinarily The valve assembly members mentioned herecause serious damage. However, when such eninbefore are all known in the art and such memgines drive compressors or pumps which transbers, and valve assembly, in one form or another fer or compress combustible gases, as natural are standard equipment for many gas engines gas or petroleum refinery gas, or volatile liquids, on the market. such as propane, butane, or gasoline, any leak- Even though the packing 9 is well lubricated age in the vicinity of the ignition end of the gas and is compressed tightly by the action of the engine provides a potential hazard and explosions gland member 8 and gland nut 1, some leakage of of serious consequence may occur. combustible gaseous fuel occurs, and this leakage One object of my invention is to provide a fuel when close to a Spark p u y es lt in safety device to assist in preventing explosions small explosions and fires, as hereinbefore mencaused by valve stem leakage. tioned. This leakage is reasonable to expect at Another object of my invention is to provide least to some extent since the fuel gas passes a safety device to assist" preventing explosions through the channel I3 from inlet point I2 toward the valve head 2 at pressures of the order of 20 pounds per square inch. leakage is further to be expected due to rather rapid longitudinal motion of the valve stem when the englue is operating. Such engines frequently operate for long periods of time without interruption.

It is known that by tightening of such a packing gland leakage may be stopped but such packing tightening frequently causes excessive packing wear and may result in gas leakage. By the use of my invention such a valve may be operated without undu tightening of the packing, and in this manner one valve packing job may function for exceptionally long periods of time.

My invention for solving the problem at hand is a safety cap device which completely surrounds the spring and packing gland assembly so that combustible gas leaking through the packing cannot contact atmospheric oxygen and thereby constitute an explosive hazard.

My safety cap device is composed of a cylindrical shaped body member 2|, having a side wall opening 22 threaded for taking a tube member 29. One end of this cylindrical body is turned in" to provide an inner flange bearing surface for contact with the valve body, as indicated by reference numeral 23. The other end of the cylindrical body member 2| is turned out so as to provide an outer flange 24 for attachment of a diaphragm 25 and ring 26. This flange is drilled and the holes may or may not be threaded and takes bolts for fixing a diaphragm 25 and a ring 26 in position, as indicated.

The tappet end of the valve stem is threaded to take some diaphragm lock nuts 21. Other means may be used for attaching the diaphragm to the valve stem, however, providing a substantially gas-tight connection can be made. In some cases the thickness of the spring retainer washer [8 should preferably be reduced in order to make room at the threaded end of the valve stem for the thickness of the two diaphragm lock nuts 21 and the diaphragm 25. However, if the valve stem is sufficiently long, the retainer washer l8 may not need be reduced in thickness.

A gasket 28 provides a substantially gas tight seal so that combustible gas cannot leak out at this point.

The side wall opening 22 is threaded to take a small diameter tubing 29 to serve as a vent line to conduct gases from this safety cap to a point at which there is no danger of an explosion. I have, in one installation, run such a vent line out a window'so that the combustible gas may be dissipated in the atmosphere,

As an example, I have used a inch thick diaphragm in a safety cap as herein disclosed, and have obtained long life of the diaphragm. In normal operation, such valves move only about V8 to 1?! inch, and this small movement assists in promoting long diaphragm life.

. The diaphragm may be made of any suitable material providing it is designed to withstand such movement as necessitated by opening and closing of the valve. Standard diaphragms, commercially available, may be used and have served well. Thus, especially designed and manufactured diaphragms are not required.

The cylindrical shaped body member, also, may be made of any material desired, such as brass or iron or steel. An advantage in the use of brass is that there is no opportunity for rusting. However, even with the use of an iron or steel member, there is little chance for rusting since such parts are usually oily from valve stem or other lubrication.

To install a safety-cap device, it is merely necessary to remove the valve, thread the tappet end of the stem, place the valve back in its original position. Repack or otherwise adjust the packing gland assembly to permit free valve stem movement, Then position the cylindrical shaped body member 2| and gasket 28, insert the valve spring and spring retainer washer. One of the lock 'nuts is positioned on the threaded portion of the valve stem, the diaphragm 25 and the second of the lock nuts added. The second of the lock nuts is tightened sufiiciently that there may be little or no gas leakage at this point. The diaphragm ring 26 is fastened in place by small bolts 30 sufliciently tight to make a tight connection. A vent tube is then inserted into-the side connection 22 of the body member 2| and extended out a window or to other disposal as desired. With an adjustment of valve tappets and the rocker arm (not shown), the valve is then ready for operation.

It will be obvious to those skilled in the art that many variations and modifications of my safety cap may be made and yet remain within the intended spirit and scope of my invention.

Having disclosed my invention, I claim:

1. A device for preventing explosions in the vicinity of a fuel gas injector valve of a gas engine operating on fuel gas under superatmospheric pressure, said injector valve being a poppet valve having a valve head and a valve stem positioned within a valve body. the valve stem extending through a packing gland assembly in said valve body, and said valve head being held on a valve seat through action of a valve spring surrounding the tappet end of said valve stem, said packing gland assembly being subject to leakage of said superatmospheric fuel gas, comprising a cylindrical shaped, hollow body member having an inside flange on one end and an outside flange on the other end, said one end being placed in a substantially gas tight position against said valve body and the hollow body member surrounding said packing gland assembly and valve spring, the outside flange end of said body member fitted in a gas tight manner with a diaphragm, said valve stem extending through and being rigidly fixed to said diaphragm in a substantially gas tight manner; and a tube means connecting said hollow body member and a point remote from said valve forming gaseous communication between said hollow body member and said remote point.

2. A safety cap devic adapted to be applied to gas engine poppet valves operating on fuel gas under superatmospheric pressure, the poppet valve stem extending through a packing gland assembly, a valve body wall and a helical valve spring in a conventional poppet valve manner, comprising a hollow cylindrical body member having an inner flange at one end and an outer flange at the other end and a side opening, said cylindrical body member being positioned around the tappet end of the valve stem in such a manner that the longitudinal axes of the body member and the valve stem substantially coincide, and with the inner flange end of said body member positioned in a substantially gas tight manner adjacent the valve body, a diaphragm in substantially gas tight relation with the outer flange end of said body member and said valve stem extending through said diaphragm and attached thereto in a substantially gas tight manner; and

5 i 6 a tubular member connected with said side open- UNITED STATES PA'I'ENTS ing of the hollow cylindrical member and com- Number Name Date municeting with a remote point for venting leak- 306,314 Beechey Oct 7, 1884 age fuel gas from said cylindrical body member 1,602.30 Held; Oct 1926 to said pointe 5 1,682,499 Gehres Aug. 2a, 1928 4 MELVIN EMERY- 1,995,572 Lower Mar, 26, 1935 REFERENCES CITED 1,992,902 McIntosh Feb. 26, 1935 2,122,398 Harrison July 5, 1938 The following references are of record in the file of this patent: 

